Semiconductor devices typically include a plurality of elements, such as transistors, formed on a semiconductor substrate. In order to electrically isolate these elements, a film such as a spin on glass (SOG) film having relatively good gap-filling characteristics may be used. However, such a film may have a relatively high impurity density and/or a relatively high etching rate as-deposited. Therefore, a furnace annealing process performed at a relatively high temperature may be used to decrease an impurity concentration or impurity density within the film and/or to increase the etch resistance of the film.
However, the temperature of the furnace annealing process that may be required to achieve a suitable impurity density and/or etch resistance may be about 900° C. or higher. Thus, device characteristics may be degraded during such a furnace annealing process.